The present invention relates to flooring systems especially designed for facilities that house data processing equipment such as data processing centers, computer rooms, and offices where there is a false floor raised above the existing floor. Such false floors or raised panel floors typically utilize removable panels laid side-by-side upon raised support members in order to afford a free space where conduit, cables, hoses, wires and other computer interconnections can be routed.
Many false flooring systems exist, including ones that use adjustable jacks at each panel corner as a means of support. The support jacks for such systems are only located at the corners of the panels, which are usually square with sides of 500 to 600 mm. Accordingly, rigidity and mechanical stability of the floor must be achieved through the use of very thick panels, usually 30 to 40 mm thick, sometimes including a framework which transfers the load to the jacks. Due to the loss of usable height, these types of false flooring require an overall height of 150 to 200 mm, which is incompatible with low ceilings in existing buildings and requires new facilities to be built with added height. As an example, if one considers a 200 mm false floor at each level of a thirty-story building, the additional required height becomes six meters, the equivalent of two stories. Installing such a false floor in existing buildings requires the construction of ramps and steps as well as fire and soundproofing barriers. Finally, such structures are sometimes noisy and act as resonators. In any event, installing existing false floors either as part of a building renovation or in new construction, is both involved and costly.
Many other false flooring systems utilize base plates from which rise protrusions that will support a floor panel. For instance, U.S. Pat. No. 5,052,157 (the "'157 patent"), incorporated herein in its entirety by this reference, describes an excellent "Flooring System Especially Designed for Facilities Which House Data Processing Equipment." The system described in the '157 patent solves many of the problems associated with previous systems, including such problems described above. However, the '157 patent contemplates and illustrates construction of portions of the system "by heat forming or injection molding of a plastic compound such as polystyrene, polyethylene, polypropylene or ABS."
While such materials are excellent choices for the formation of the components for which they are suggested in the '157 patent, particularly in view of the complex shapes of some of those components, drawbacks are associated with the use of such materials in certain applications. First, the load-bearing capacity of a raised panel flooring structure utilizing such plastic materials is, in part, a function of the quantity and type of plastic materials utilized, and it can be difficult to achieve high load-bearing capacities with such plastic structures at acceptable costs and without undesirable weight. Additionally, although the nature of the application and the use of flame-retardant and smoke-suppression formulations and additives can make use of such plastic materials acceptably safe as construction materials, some fire codes nevertheless limit or prevent the use of plastic structures as components of raised panel flooring.
Accordingly, the assignee of the present invention developed the low profile raised panel flooring with a metal support structure described in U.S. Pat. No. 5,675,950 ('950 patent ), incorporated herein in its entirety by this reference. The '950 patent discloses "thin sheet metal, typically galvanized steel, base plates laid side by side on the existing floor, on which stand-offs are attached in a rectilinear pattern to serve as supports for floor panels that form the raised or false floor and are typically covered with carpet tile." Each stand-off has "a! tab on the end of each arm of each stand-off that! is received with a friction fit in an opening in the baseplate, and is bent to lie against the underside of the base plate in a depression formed therein." Thus, the stand-offs may be assembled into the base plate, which can be provided with "s! core or cutting lines . . . for breaking or to facilitate cutting it during installation."
The metal support structure disclosed in the '950 patent provides a non-combustible, enhanced load-bearing and easily assembled flooring system. However, the costs of the metal flooring system may be significantly higher than the plastic materials that are used with systems such as disclosed in the '157 patent. Obviously, the higher cost is a function of the generally more expensive metal (in terms both of costs of material and more involved manufacturing processes) that comprises the base plates and stand-offs. Moreover, the necessity of separately manufacturing base plates and stand-offs, then assembling them, adds complexity (and consequently increased cost) to the flooring system. Indeed, the assembled flooring system may also have significant weight, in the range of 10-12 kilograms per square meter of flooring. This weight, in addition to the bulk of the metal base plates, makes more difficult not only the storing and transportation of the metal base plates, but also their application to the floor to be provided with the flooring system. Moreover, in multi-floor buildings that have large areas to which a flooring system must be applied, a decrease in the weight of the flooring system is cumulatively significant and therefore desirable in order to decrease the load on the building's structure.
Furthermore, when the ultimate user assembles the base plates upon the floor, she may find it difficult properly to shape the base plates to fit odd corners or spaces remaining once the rest of the floor is covered. Although this problem is reduced by the scoring or weakening provided in the base plate, which allows some flexibility in shaping the base plate to match the area to be covered, it still slows the process of installing the flooring system in the event that the user must laboriously and carefully cut through the entire base plate to give it the appropriate shape.
Accordingly, there remains a need for a low profile raised panel flooring system using components compatible with the strictest fire codes, that can offer high load-bearing capacity, is cost effective and overcomes other disadvantages of the above systems.